When a pigment is used as a colorant, an ink composition is prepared by mixing the concentrated pigment dispersion which contains pigment, water, dispersant and the like with water, resin, a water-soluble organic medium, and other ingredients.
In ink compositions, the pigment dispersion is generally stabilized by a dispersant which serves to prevent the pigment particles from agglomerating and settling out of the carrier. While prior ink compositions showed acceptable stability for the pigment dispersion, improved pigment dispersion is still needed to further lower the ink viscosity, impart better print density, increase pigment loading, and lower milling times for ink and coating systems.
Therefore, an improved dispersant is needed.